1. Field of the Invention
This invention relates to compression refrigeration systems and evaporative coolers for use in human and animal habitations.
2. The Prior Art
Apparatus employing the standard vapor compression system of refrigeration embodied both in package and split systems are widely used throughout the country to heat residential and commercial structures in which man and animals are housed and wherein their possessions are stored. Such structures will hereafter be referred to as habitations.
In the split system the expansion coil and a fan are located in an air plenum inside the habitation and the compressor and condenser are situated somewhere outside. Refrigerant lines communicate between the inside and outside elements. In the package units the entire cycle of compression and expansion functions are in one housing, usually outside the building, with only the duct work going into the habitation.
In certain areas where low relative humidity prevails a relatively inexpensive-to-operate evaporative cooler, which cools by blowing air into the habitation after passing it through a water-saturated pad of excelsior or the like, is used to reduce the inside dry bulb temperature. Although the evaporative cooler is inexpensive to operate compared to compression refrigeration, its moisture laden air increases relative humidity and, therefore, does not create a comfortable environment when the weather is humid. Another disadvantage is that it creates excessive air motion because of the large air volume required. The introduction of humidity into the air requires that the air be circulated once and exhausted. The habitation air cannot be recirculated through the evaporative cooler because low humidity air is required for the evaporative cooling process.
The prior art workers used evaporative cooling as a pre-cooler to blow air directly on the condenser coil to cool it in the hope of enhancing the efficiency of the refrigeration system. The method is to install a cooler pad covering the inlet of the refrigeration case and provide means for trickling water over the pad.
This apparatus is scarcely more efficient than using compression refrigeration apparatus alone. Although merely providing means for cooling the refrigerant after it leaves the expansion coils helps to cool and therefore condense it, the air flow is reduced by the cooler pads. A second or more powerful motor is added to increase the flow and the increased load requires more power, offsetting the savings. In cooler weather the load is still carried even though not needed. Even the most efficient pre-cooler arrangement has no more than 10 percent increase in efficiency claimed for it, and in practice much less is probably realized.